Recovery of sulphur



My 11 1933 R. F. BACON Er AL 1,917,787

RECOVERY oF sULPHUR Filed Feb. 25, 1930 RyrvlOND FTBRQQN Rocco F'NELLI BY "Pw ATTORNEYS ui i Patented July 11,1933

UNIT-ED .STATES Parentl FFICE RAYMOND r. BACON, or BRONXVILLE, Ann Rocco Ferretti. or nii-fur' Boonstra, YORK; sain rANELLr assieivor sain encon l RECOVERY OF S'ILPI-IUBI Application filed February 25, 1930. 'Serial'Nd This invention relates to the recovery of sulphur and has for an ob]ect the provision of an improved process tor recovering sulphur from heavy metal sulphide ores. More 5l particularly, the invention contemplates the provision otan improved process for recovering sulphur from materials containing. one or more sulphidesv ot iron. The invention further contemplates the provision of an iinl proved process for treating heavy metal sulphide ores, such, for example, as ore containing sulphides of iron, copper and nichel.

The process ot'the present invention involves the treatment of ore or other metallurgical raw materials or products containing pyrites or other sulphides of iron, alone or in vcombination with sulphides of other heavy'metals, Such, for example, as copper and nichel With a chlorinating agent such, for example, as chlorine, sulphuryl chloride o-r sulphur chloride for the purpose ot' obtaining tree sulphur and/or separating iron from the mass ot material undergoing treatment; Y

In carrying Vout 4a process in accordance with the present invention, a quantity of the material. to be treatedy is subjected to the action ot a chlorinatiug agent under such conditions that ferrous chloride and free sulphur are formed. The process is so conducted that the sulphurl produced is vaporized, leaving a residue containing the ferrous' chloride together with chlorides of other' heavy metals such as copper and niclrel when the sulphides ot such metals are present in the material being treated. The residue containing ferrous chloride is subjected tothe action of air and steam to produce hydrogen chloride..

The hydrogen chloride produced is dried and subjected to the action of air in t-he presence of a suitable catalyst to produce free chlorine which is returned to the processs.

The invention will be better understood from a consideration of the accompanying {iowsheet and the following description of the application of the process to the treatment ot' ore containing sulphidcs of copper, nickel and iron, with sulphur chloride.

The ore to be treated is subjected to the action oit sulphur chloride under such conditions that ferrous chloride and treersulphur are produced. The operation is so conducted that the sulphur produced is vaporized, leavin@` -a residue containing the 'terrous chloride together with the chlorides of l' The sulphur may beV end. Sulphur chloride is introduced into the reaction chamber at the end opposite to thatk n at which the ore is introduced and the ore and sulphur chloride pass throughthe re-y action chamber in counter-'current relationship. into the reactionl chamber as a. liquid or as a4 gas. Liquid sulphur chloride will be vaporiZed immediately aft-er its introduction. l

Sulphur chloride may be introduced :H

The ore is preferably ground toprovide par- Y ticles suliciently small to pass 1GO-mesh screen in order 'that intimate contact of the sulphur chloiidevvith the sulphide particles mayr be obtained.

'l'he .process is preferably so. controlled that a temperature oi aboutlOo C. is maintained LL-? near the charging end ofthc'i'eaction lcharnber, and a temperature ot aboutOOo C. to 850 C. is maintained near the Adischarge end ofthe reaction chaniher.- rlhc admission oi ore. and sulphur chloride are so regulated that all of the sulphurl liberated is vaporized vand all oi the sulphur chloride admitted is consumed. The sulphur produced is vapor-- ized and separated from the heavy metal chlorides in the hottest portion otl the reaction chamber, and the residue containing the heavy metal chlorides is discharged from the gictin chamber at a temperature. of about The hot residue containing ferrous chloride and the chlorides of nickel and copper is treated with steam in order to produce hydrogen chloride and oxides of the metals by hydrolysis. Air is admitted with the steam in order to assist the reaction by oxidation of the iron. The air and steam are preheated in order to assist in maintaining the mass at the desired reaction temperature. Y

The hydrolysis will take place at normal atmospheric temperatures, but the rate of reaction is too slow for practical purposes. Higher temperatures not only increase the speed of the hydrolysis butalso assist in the air oxidation which takes place. The treatment u of the ferrous chloride-bearing material with air and steam may be carried out satisfactorily at a temperature of from 4400 C. to 6000 C. Ordinarily, a reaction temperature of about 5000 C. is entirely satisfactory.

The treatment of the ferrous chloridebearing material with air and steam may be carried out conveniently in a rotary reaction chamber having charging means at one end and discharging means at the opposite end and which is so constructed and arranged that the material passes from the charging end to the discharge end during its rotation. The ferrous chloride-bearing material and the air and steam are introduced into the reaction chamber at the charging end and the resulting heavy metal oxides and hydrogen chloride are removed from the reaction chamber at the discharge end. The oxides and hydrogen chloride are preferably removed through separate discharge outlets. If the hydrogen chloride gas leaving the chamber carries considerable amounts of entrained particles of oxides it may be desirable to provide a settling chamber into which the oxides and hydrogen chloride Amay he introduced from theV reaction chamber. Such a chamber should be maintained at a sufficiently high temperature to prevent the reverse reaction.

Means such, for example, as porcelain balls or other large pieces of inert materials are provided within the reaction chamber to prevent the chlorides from adhering to the walls of the chamber.V Such means aid in stirring and grinding the chlorides and oxides as they pass through the reaction chamber.

The gases issuingffrom the reaction chamber contain hydrogen chloride and water vapor and they are passed through a suitable drying apparatus such, for example, as a packed tower having sulphuric acid trickling therethrough to separate the water vapor and produce dry hydrogen chloride.

The dry hydrogen chloride is introduced into a catalytic reaction chamber with one to seven times its volume of air, depending on the concentration of the hydrogen chloride available. The air is preheated to a temperature above 4200 C, and preferably to a temperature between 520 and 5300 C. If

desired, the hydrogen chloride may also be preheated.

The catalytic reaction chamber preferably consists of a tower, or a series of communicating towers packed with a material l'laving a very large surface per unit of volume such, for example, as vpumice, brick, cinders and the like. The packing material should be of such a natur-e that it will be inert to the reagents and the products of the reaction. The paci-:- ing material is covered or impregnated with the catalyst which may be one or more chlorides or sulphates of metals such, for example, as copper and nickel. rllhe salts may be applied such directly to the packing material or they may be formed in place as, foi` example,'by the action of hydrogen chloride on copper oxide which is distributed throughout the mass. Means are provided for renewing the catalytic mass as its etliciency becomes reduced. For this purpose two towers or two series of communicating towers which may be used alternately are preferably provid-.eI

A portion ofthe mass of oxides resulting from the treatment of the ferrous chloridebearing material with steam and air may he utilized as a catalytic agent for promoting the reaction between the hydrogen chloride and oxygen.

The apparatus is so constructed that the mass of catalyst-bearing material may be maintained at a temperature of from 3700 C. to 4000 C. The reaction between the hydrogen chloride and the oxygen of the air is exothermicand it may be so controlled as to permit the proper temperature to be maintained. The reaction will proceed at temperatures as low as 2050 C., and temperatures as high as 4700 C. may be used advantageously. The temperature at which the reaction is conducted will be governed largely by the nature of the catalyst. The temperature employed should be suthciently low that excessive volatilization of the catalyst is avoided. The reaction involved in this operation does not proceed to completion. The gases issuing from the reaction chamber will consist of a mixture of hydrogen chloride, water vapor and chlorine.

.ln view of the fact that the reaction does not readily proceed to completion, it may be desirable to retreat the issuing gases by subjecting them to a drying operation to remove the water vapor and subsequently passing them through a second reaction chamber. This procedure maybe repeated two or three or more times if desired.v In carrying out the reaction between hydrogen chlorideand the oxygen of air it is advisable to carefully control the proportions of air and hydrogen chloride utilized in order to avoid excessive dilution of the resulting chlorine gas.

The gases containing hydrogen chloride and chlorine are washed with water to separate the chlorine and hydrogen chloride. The

Lea-7,78??

resulting solution ot hydrogen chloride in Water may be treated in any suitable man-ner to recover the hydrogenchloride..

The chlorine recovered is dried and the dry i chlorine is passed through a bath of molten sulphur which has been obtained by condensing a portion of the sulphur vapor recovered f to eilect the immediate removal of the sulphur,

chloride from the reaction zone. Condensation oit the sulphur chloride permits the escape of inert gases which enter the system during` the admission of air. lt desired, the inert gases may be conducted through a tower ot'- solid sulphur in order to sci-ub out any sulphur chloride vapors contained therein. V

The process may be conducted continuously. A, source of supply of fresh chlorine is provided. to compensate for chlorine losses due tol-ealzage and other causes, Thetresh.

chlorine maybe supplied as free chlorine, sulphur chloride or hydrogen chloride, and the choice will depend upon the relative costs.

le claim: l y

' l. The method of recovering sulphur from iron sulphide-bearing material containing sulphides ot one or more other' heavy metals which comprises subjecting the material to the action of a chlorinating agent under such conditions that elemental sulphur and a dry, substantially non-fused product containing` ferrous chloride and chlorides of such. other`| heavy metals as may `loe present in the material are torined and thesulphur isvaporized,

subjecting tlieV combined chloride product directly to the action of steam and' air to produce simultaneously hydrogen chloride and oxides ot the heavy met-als, treating' thehydrogen chloride to recover chlorine, and returning' the chlorine thus recovered to the process 2. rfhe method of recovering,r sulphur from iron .sulphide-bearing material containing sulpliides oi one or more other heavy metals which comprises subjecting the material to the action of a chlorinating agent under such conditions that elemental sulphur and a dry, substantially non-fused product containing` ferrous chloride and chlorides of such other heavy metals as may be present in the material are 'formed and the sulphur is vaporized, subjecting the combined chloride product directly to the action of steam and air to produce simultaneously hydrogen chlo- The sulphur ride and oxides of the heavy metals, subjectingl the hydrogen chloride tothe action of air in theV presence ofk a catalyst to recover ehlorine, and returning the chlorine thus recovered to the process.

3. rEhe method of recovering sulphur from iron sulphide-bearing material containing sulphides of one or more other heavy metals which comprises subjecting' the material to vthe action of sulphur chloride under such conditions that elemental sulphur and a drysubstantially non-fused product containing ferrous chloride and chlorides of such other heavy metals as may be present in the mat-e rial are formed and the sulphur is vaporized, subjecting, the combined chloride product directly to the action of steam and air to produce simultaneously, hydrogen chloride and oxides ot the heavy metals7 treating the hydrogen chloride to recover chlorine, andl returning` the chlorine thus recovered to the l process. r

4. The method of recovering sulphur from iron sulphide-bearing material containing; :uilphides ot one or more other heavy metals which comprises subjecting' the material to the action of sulphur chloride under such conditions that elen'iental' sulphur and a drysiibstantially non-fused product containing` ferrous chloride and.Y chlorides of such other metals as may be present in the material are formed and the sulphur is vapor- Zed, subjecting the combined chloride proddirectly to the action of steam and air produce simultaneously hydrogen chloride dan the hydrogen chloride to thonet-ion ot air in: the presence of a catalyst to recover chlorino` and returning' the chlorine thus recovered tothe process. The method ofrecoveringv sulphur troni iron Vsulphiile-bearingi material. c iit:|.-iiiiiie; sulpliides et one or more other heavy -i'netals `which comprises subjecting' the material to the action-ot? a chlorinati-ng ag'entunder such condi ionsthat elemental sulphur and' a drv `substantially i1,on'tused product containing 'ferrous chloride and chlorides oi such other heavy metals as may lie present in the material are formed and the sulphur is 15a-poi ized, subjecting' the combined chloride izuodf uct directly'to the action of steam and air to produce simu]taneously hydrogen chloride and oxides of heavy nietas, snbjecti'ng'the hydrogen chloride to the action of oxygen in the presence of the oxides produced to .recover chlorine, and returning` the chlorine thus recovered to the process.

6. The method of recovering; sulphur from iron sulphide-bearing material containing` sulphides of one or more other heavy metals .which comprises `subjectirne` the materialto the action of sulphur chloride under such conditions that elemental sulphur and a dry,

oxides oithe; heavy metals, subjecting` Y substantially non-fused product containing ferrous chloride and chlorides ol' such other heavy metals-asmay be present in the material are 'formed and the sulphur is vaporized,

V subjecting lthe combined chloride product directly to the action of steam and air to produce sinnlltaneously hydrogen chloride and oxides of the heavy metals, treating the hydrogen chloride to recover chlorine, combining the chlorine thus recovered n-'ith a portion ol the sulphur produced to regenerate sulphur chloride, and utilizing the sulphur chloride thus produced to treat additional iron sulphide-bearing material.

T. The method oi recovering sulphur from iron sulphide-hearing material containingl sulphidcs ot' one or more other heavy metals which comprises subjecting the material to the action ot' sulphur chloride under such conditions that elemental sulphur and a dry- ::ul,-si'antially non-fused product containing ferrous chloride und chlorides ot such other heavy metals as may be present Vin the material are formed and the sulphur is vaporized, ,subjecting the combined chloride product directly to the action ol steam and air to produce simultaneously hydrogen chloride and oxides oli the heavy metals, subjecting the hydrogen chloride to the action oli air in the presence et u catalyst 4to recover chlorine. combining the chlorine thus recovered with a portion of the sulphur produced to regenerate sulphur chloride, und util'zing the sulphur chloride thus produced to treat additional iron sulphide-bellring material.

8. The method of recovering sulphur from iron sulphide-hearing material containing sulphides of one or more other heavy metals which comprises subjecting the material to the act-ion of sulphur chloride under such conditions that elemental sulphur and a dry, substantially non-fused product containing ferrous chloride and chlorides of such other heavy metals as may be present in the mate rial are formed and the sulphur is vaporized, subjecting the combined chloride product directly to the action of steam and air to produce simultaneously hydrogen chloride and oxides of the heavy metals, treating the hydrogen chloride to recover chlorine, passing the resulting chlorine-hearing gases in contact with molten sulphur to produce and vaporize sulphur chloride, condensing` the sulphur chloride thus produced to separate inert gases, vaporizing the condensed sulphur chloride, and utilizing the vaporized sulphur chloride to treat additional iron sulphide-bearing material.

9. rlhe method of recovering sulphur from iron sulphide-hearing material containing sulphides of one or more other heavy metals which comprises subjecting the material to the action of sulphur chloride under such conditions that e einental sulphur and a dry, substantialhv non-fused product containing ferrous chloride and chlorides of such other heavy metals as may be present in the material are formed and the sulphur is vaporized, subjecting the combined chloride product directly to the action of air and steam at a temperature of about l0-O C. to 600 C. to produce simultaneouslyhydrogen chloride and oxides of the heavy metals, treating the hy drogen chloride to recover chlorine, combining the chlorine thus recovered with a portion olf the sulphur produced to regenerate sulphur chloride, and utilizing the sulphur chloride thus produced to treat additional iron sulphide-bea rin g material.

l0. The method of recovering sulphur from iron sulphide-bearing material containing sulphides of one or more other heavy metals which comprises subjecting the material to the action ol sulphur chloride under such conditions that elemental sulphur and a dry, substantially non-:fused product containing' ferrous chloride and chlorides of such other heavy metals as may he present in the material arc formed and the sulphur is vaporized, subjecting the combined chloride product directly to the action of air and steam at a temperature of about 4400 C. to 600o C. to produce simultaneously hydrogen chloride and oxides of the heavy metals, treating the hydrogen chloride to recover chlorine, passing the resulting chlorine-bearing gases in contact with molten sulphur to produce and vapor'ize sulphur chloride, c0ndensing the sulphur chloride thus produced to separate inert gases, vaporizing the condensed sulphurv chloride, and utilizing the vaporizcd sulphur chloride to treat additional iron sulphide-bearing material.

ln testimony whereof We affix our signatures.

RAYMOND F. BACON. RGCCO FANELLI. 

